Load Terms Used in the Member Report
Load Type (found in the Loads grid)
- Seven (7) load types, or load cases, are available to be applied to members for analysis in ForteWEB software:
- Dead (D)
- Floor Live (L)
- Roof Live (Lr) → not used in Canada (NBCC)
- Snow (S)
- Wind (W)
- Seismic (E)
- Seismic (QE) → only used for overstrength (IBC 2018 or newer)
Load Combinations
IBC 2009 Load Combinations (found in the Design Results grid)
Load Pattern (found in the Design Results grid)
Live loads are pattern loaded on multi-span bending members in the percentages shown below (load combination factors also apply). The patterns include:
- Fully loaded spans = All spans
- Fully loaded spans = Alternate spans
- Fully loaded Spans = Spans adjacent to each side of a support
| Live Load Type | Load Pattern % | Fully Loaded Span | Unloaded Span |
|---|---|---|---|
|
Floor Live (L), Wind (W), Seismic (E) |
100% pattern loading |
100% |
0% |
|
Roof Live (Lr), Snow (S) |
50% pattern loading |
100% |
50% |
Load Group (when applicable, found in the Design Results grid)
Transferring support reactions from a multi-span member to another member.
A multi-span Member A will experience Live Load pattern loading resulting in “down/up” reactions at some supports. The reaction has both positive (downward) and negative (upward) components.
The concept of load “groups” attempts to solve a problem that is encountered when the “down/up” support reaction of Member A is transferred onto Member B. The resulting positive and negative loads transferred to Member B do not occur simultaneously. That is, when applied as a load to Member B, the (+/-) values are not added together.
ForteWEB will separate non-simultaneous loads and “group” them into separate load groups before applying them to Member B. Independent analysis of Member B is then performed for each load group when running through all of the various load combinations.
Notes:
- Dead and Snow are not pattern loaded and never cause “down/up” transfer reactions. As a result, these two load cases are never placed into load groups.
- Canada (NBCC) does not use Roof Live loads and so will not contain this loading condition.
Comments about ForteWEB load group functionality:
- Transfer Loads in the Loads Tab: Applicable “down/up” loads which have been transferred from another member’s reaction (or from another software program) are always split into separate load groups and will appear in the same field in the Loads Tab; Example (495/-383). They are not adjustable in the Loads Tab.
- User Loads in the Loads Tab: Since two User Loads of the same load case cannot be entered in the same load grid field, user loads will never be split into load groups.